Reinstate BoltDB and ClevelDB as backend DBs (#177)

* Revert "remove deprecated boltdb and cleveldb (#155)"

This reverts commit badc0b8.

We decided to reinstate boltDB and clevelDB and mark them as deprecated until a
future version of CometBFT in which we'll drop cometbft-db and support only 1 backend
DB.

* updated cleveldb Iterator API docs to conform to the changes made in #168

* updated go.mod

* updated boltDB Iterator APIs to conform to the changes made in #168

* added changelog entry

* Formatting

Co-authored-by: Daniel <daniel.cason@informal.systems>

* formatting to please the linter

* added additional context in the docs of backend types constants

---------

Co-authored-by: Daniel <daniel.cason@informal.systems>

.changelog/unreleased/dependencies/177-reinstate-boltdb-cleveldb.md

@@ -0,0 +1,2 @@
+- reinstate BoltDB and ClevelDB as backend DBs
+  ([\#177](https://github.com/cometbft/cometbft-db/pull/177))

Makefile

@@ -19,11 +19,21 @@ test:
 	@go test $(PACKAGES) -v
 .PHONY: test
 
+test-cleveldb:
+	@echo "--> Running go test"
+	@go test $(PACKAGES) -tags cleveldb -v
+.PHONY: test-cleveldb
+
 test-rocksdb:
 	@echo "--> Running go test"
 	@go test $(PACKAGES) -tags rocksdb -v
 .PHONY: test-rocksdb
 
+test-boltdb:
+	@echo "--> Running go test"
+	@go test $(PACKAGES) -tags boltdb -v
+.PHONY: test-boltdb
+
 test-badgerdb:
 	@echo "--> Running go test"
 	@go test $(PACKAGES) -tags badgerdb -v
@@ -35,7 +45,7 @@ test-pebble:
 
 test-all:
 	@echo "--> Running go test"
-	@go test $(PACKAGES) -tags rocksdb,grocksdb_clean_link,badgerdb,pebbledb -v
+	@go test $(PACKAGES) -tags cleveldb,boltdb,rocksdb,grocksdb_clean_link,badgerdb,pebbledb -v
 .PHONY: test-all
 
 test-all-with-coverage:
@@ -46,7 +56,7 @@ test-all-with-coverage:
 		-race \
 		-coverprofile=coverage.txt \
 		-covermode=atomic \
-		-tags=memdb,goleveldb,rocksdb,grocksdb_clean_link,badgerdb,pebbledb \
+		-tags=memdb,goleveldb,cleveldb,boltdb,rocksdb,grocksdb_clean_link,badgerdb,pebbledb \
 		-v
 .PHONY: test-all-with-coverage
 

README.md

@@ -33,6 +33,19 @@ Go 1.22+
   sets, and tests. Used for [IAVL](https://github.com/tendermint/iavl) working
   sets when the pruning strategy allows it.
 
+- **[LevelDB](https://github.com/google/leveldb) [DEPRECATED]:** A [Go
+  wrapper](https://github.com/jmhodges/levigo) around
+  [LevelDB](https://github.com/google/leveldb). Uses LSM-trees for on-disk
+  storage, which have good performance for write-heavy workloads, particularly
+  on spinning disks, but requires periodic compaction to maintain decent read
+  performance and reclaim disk space. Does not support transactions.
+
+- **[BoltDB](https://github.com/etcd-io/bbolt) [DEPRECATED]:** A
+  [fork](https://github.com/etcd-io/bbolt) of
+  [BoltDB](https://github.com/boltdb/bolt). Uses B+trees for on-disk storage,
+  which have good performance for read-heavy workloads and range scans. Supports
+  serializable ACID transactions.
+
 - **[RocksDB](https://github.com/linxGnu/grocksdb) [experimental]:** A [Go
   wrapper](https://github.com/linxGnu/grocksdb) around
   [RocksDB](https://rocksdb.org). Similarly to LevelDB (above) it uses LSM-trees

boltdb.go

@@ -0,0 +1,213 @@
+//go:build boltdb
+// +build boltdb
+
+package db
+
+import (
+	"errors"
+	"fmt"
+	"os"
+	"path/filepath"
+
+	"go.etcd.io/bbolt"
+)
+
+var bucket = []byte("tm")
+
+func init() {
+	registerDBCreator(BoltDBBackend, func(name, dir string) (DB, error) {
+		return NewBoltDB(name, dir)
+	})
+}
+
+// BoltDB is a wrapper around etcd's fork of bolt (https://github.com/etcd-io/bbolt).
+//
+// NOTE: All operations (including Set, Delete) are synchronous by default. One
+// can globally turn it off by using NoSync config option (not recommended).
+//
+// A single bucket ([]byte("tm")) is used per a database instance. This could
+// lead to performance issues when/if there will be lots of keys.
+type BoltDB struct {
+	db *bbolt.DB
+}
+
+var _ DB = (*BoltDB)(nil)
+
+// NewBoltDB returns a BoltDB with default options.
+//
+// Deprecated: boltdb is deprecated and will be removed in the future.
+func NewBoltDB(name, dir string) (DB, error) {
+	return NewBoltDBWithOpts(name, dir, bbolt.DefaultOptions)
+}
+
+// NewBoltDBWithOpts allows you to supply *bbolt.Options. ReadOnly: true is not
+// supported because NewBoltDBWithOpts creates a global bucket.
+func NewBoltDBWithOpts(name string, dir string, opts *bbolt.Options) (DB, error) {
+	if opts.ReadOnly {
+		return nil, errors.New("ReadOnly: true is not supported")
+	}
+
+	dbPath := filepath.Join(dir, name+".db")
+	db, err := bbolt.Open(dbPath, os.ModePerm, opts)
+	if err != nil {
+		return nil, err
+	}
+
+	// create a global bucket
+	err = db.Update(func(tx *bbolt.Tx) error {
+		_, err := tx.CreateBucketIfNotExists(bucket)
+		return err
+	})
+	if err != nil {
+		return nil, err
+	}
+
+	return &BoltDB{db: db}, nil
+}
+
+// Get implements DB.
+func (bdb *BoltDB) Get(key []byte) (value []byte, err error) {
+	if len(key) == 0 {
+		return nil, errKeyEmpty
+	}
+	err = bdb.db.View(func(tx *bbolt.Tx) error {
+		b := tx.Bucket(bucket)
+		if v := b.Get(key); v != nil {
+			value = append([]byte{}, v...)
+		}
+		return nil
+	})
+	if err != nil {
+		return nil, err
+	}
+	return
+}
+
+// Has implements DB.
+func (bdb *BoltDB) Has(key []byte) (bool, error) {
+	bytes, err := bdb.Get(key)
+	if err != nil {
+		return false, err
+	}
+	return bytes != nil, nil
+}
+
+// Set implements DB.
+func (bdb *BoltDB) Set(key, value []byte) error {
+	if len(key) == 0 {
+		return errKeyEmpty
+	}
+	if value == nil {
+		return errValueNil
+	}
+	err := bdb.db.Update(func(tx *bbolt.Tx) error {
+		b := tx.Bucket(bucket)
+		return b.Put(key, value)
+	})
+	if err != nil {
+		return err
+	}
+	return nil
+}
+
+// SetSync implements DB.
+func (bdb *BoltDB) SetSync(key, value []byte) error {
+	return bdb.Set(key, value)
+}
+
+// Delete implements DB.
+func (bdb *BoltDB) Delete(key []byte) error {
+	if len(key) == 0 {
+		return errKeyEmpty
+	}
+	err := bdb.db.Update(func(tx *bbolt.Tx) error {
+		return tx.Bucket(bucket).Delete(key)
+	})
+	if err != nil {
+		return err
+	}
+	return nil
+}
+
+// DeleteSync implements DB.
+func (bdb *BoltDB) DeleteSync(key []byte) error {
+	return bdb.Delete(key)
+}
+
+// Close implements DB.
+func (bdb *BoltDB) Close() error {
+	return bdb.db.Close()
+}
+
+// Print implements DB.
+func (bdb *BoltDB) Print() error {
+	stats := bdb.db.Stats()
+	fmt.Printf("%v\n", stats)
+
+	err := bdb.db.View(func(tx *bbolt.Tx) error {
+		tx.Bucket(bucket).ForEach(func(k, v []byte) error {
+			fmt.Printf("[%X]:\t[%X]\n", k, v)
+			return nil
+		})
+		return nil
+	})
+	if err != nil {
+		return err
+	}
+	return nil
+}
+
+// Stats implements DB.
+func (bdb *BoltDB) Stats() map[string]string {
+	stats := bdb.db.Stats()
+	m := make(map[string]string)
+
+	// Freelist stats
+	m["FreePageN"] = fmt.Sprintf("%v", stats.FreePageN)
+	m["PendingPageN"] = fmt.Sprintf("%v", stats.PendingPageN)
+	m["FreeAlloc"] = fmt.Sprintf("%v", stats.FreeAlloc)
+	m["FreelistInuse"] = fmt.Sprintf("%v", stats.FreelistInuse)
+
+	// Transaction stats
+	m["TxN"] = fmt.Sprintf("%v", stats.TxN)
+	m["OpenTxN"] = fmt.Sprintf("%v", stats.OpenTxN)
+
+	return m
+}
+
+// NewBatch implements DB.
+func (bdb *BoltDB) NewBatch() Batch {
+	return newBoltDBBatch(bdb)
+}
+
+// WARNING: Any concurrent writes or reads will block until the iterator is
+// closed.
+func (bdb *BoltDB) Iterator(start, end []byte) (Iterator, error) {
+	if (start != nil && len(start) == 0) || (end != nil && len(end) == 0) {
+		return nil, errKeyEmpty
+	}
+	tx, err := bdb.db.Begin(false)
+	if err != nil {
+		return nil, err
+	}
+	return newBoltDBIterator(tx, start, end, false), nil
+}
+
+// WARNING: Any concurrent writes or reads will block until the iterator is
+// closed.
+func (bdb *BoltDB) ReverseIterator(start, end []byte) (Iterator, error) {
+	if (start != nil && len(start) == 0) || (end != nil && len(end) == 0) {
+		return nil, errKeyEmpty
+	}
+	tx, err := bdb.db.Begin(false)
+	if err != nil {
+		return nil, err
+	}
+	return newBoltDBIterator(tx, start, end, true), nil
+}
+
+func (bdb *BoltDB) Compact(start, end []byte) error {
+	// There is no explicit CompactRange support in BoltDB, only a function that copies the
+	// entire DB from one place to another while doing deletions. Hence we do not support it.
+	return nil
+}

boltdb_batch.go

@@ -0,0 +1,87 @@
+//go:build boltdb
+// +build boltdb
+
+package db
+
+import "go.etcd.io/bbolt"
+
+// boltDBBatch stores operations internally and dumps them to BoltDB on Write().
+type boltDBBatch struct {
+	db  *BoltDB
+	ops []operation
+}
+
+var _ Batch = (*boltDBBatch)(nil)
+
+func newBoltDBBatch(db *BoltDB) *boltDBBatch {
+	return &boltDBBatch{
+		db:  db,
+		ops: []operation{},
+	}
+}
+
+// Set implements Batch.
+func (b *boltDBBatch) Set(key, value []byte) error {
+	if len(key) == 0 {
+		return errKeyEmpty
+	}
+	if value == nil {
+		return errValueNil
+	}
+	if b.ops == nil {
+		return errBatchClosed
+	}
+	b.ops = append(b.ops, operation{opTypeSet, key, value})
+	return nil
+}
+
+// Delete implements Batch.
+func (b *boltDBBatch) Delete(key []byte) error {
+	if len(key) == 0 {
+		return errKeyEmpty
+	}
+	if b.ops == nil {
+		return errBatchClosed
+	}
+	b.ops = append(b.ops, operation{opTypeDelete, key, nil})
+	return nil
+}
+
+// Write implements Batch.
+func (b *boltDBBatch) Write() error {
+	if b.ops == nil {
+		return errBatchClosed
+	}
+	err := b.db.db.Batch(func(tx *bbolt.Tx) error {
+		bkt := tx.Bucket(bucket)
+		for _, op := range b.ops {
+			switch op.opType {
+			case opTypeSet:
+				if err := bkt.Put(op.key, op.value); err != nil {
+					return err
+				}
+			case opTypeDelete:
+				if err := bkt.Delete(op.key); err != nil {
+					return err
+				}
+			}
+		}
+		return nil
+	})
+	if err != nil {
+		return err
+	}
+	// Make sure batch cannot be used afterwards. Callers should still call Close(), for errors.
+	return b.Close()
+}
+
+// WriteSync implements Batch.
+func (b *boltDBBatch) WriteSync() error {
+	return b.Write()
+}
+
+// Close implements Batch.
+func (b *boltDBBatch) Close() error {
+	b.ops = nil
+	return nil
+}